Geometry Vocabulary
Terms
undefined, object
copy deck
- angle of depression
- the angle formed by a horizontal line and the line of sight to an object below the horizontal line
- plane
- (undefined) a two-dimensional set of points that are not on the same line (flat surface)
- vector
- any quantity with magnitude (size) and diretion
- cone
- "pointed like a pyramid", but its base is a circle
- circumscribed about
- when the vertices of the polygon are on the circle
- glide reflectional symmetry
- a glide reflection maps the tessellation onto itself
- chord
- a segment whose endpoints are on a circle
- linear pair
- two angles form this if and only if they are adjacent angles whose noncommon sides are opposite rays
- terminal point
- the second point in a vector
- edge
- a segment that is formed by the intersection of two faces
- composition
- a combination of two or more transformations
- image
- resulting figure
- magnitude
- size
- straightedge
- a ruler with no makings on it
- parallelogram
- a quadrilateral with both pairs of opposite sides parallel
- compass
- geometric tool used to draw circles and archs
- congruent angles
- angles with the same measure
- transversal
- a line that intersects two coplanar lines at two distince points
- vertex
- a point where three or more edges intersect
- inverse
- negates both the hypothesis and the conclusion
- minor arc
- an arc that is smaller than a semicircle
- oblique prism
- some or all of the lateral faces are nonrectangular
- congruent arcs
- arcs that have the same measure and are in the same circle or in congruent circles
- arc length
- a fraction of a circle's circumference
- skew lines
- noncoplanar (not parallel, do not interset)
- standard form of an equation of a circle
- (x-h)^2 + (y-k)^2 = r^2
- diameter
- a segment that contains the center of the circle and whose endpoints are on the circle
- intercepted arc
- an arc of a circle having endpoints on the sides of an inscribed angle, and its other pints in the interior of the angle
- surface area
- the sum of the lateral area and the area of the two bases
- incenter of the triangle
- the point of congurency of the angle bisectors of a triangle
- legs
- the congurent sides of an isosceles triangle
- complementary angles
- two angles whose measures have the sum of 90
- glide reflection
- the composition of a glide (translation) and a refletion in a line parallel to the glide vector
- reduction
- gets smaller
- angle
- formed by two rays with the same endpoint
- scale
- the ratio of any length in a scal drawing to teh corresponding actual length
- segment of a circle
- a part of a circle bounded by an arc and the segment joining its endpointss
- sine
- leg opposite / hypotenuse
- golden rectangle
- a rectangel that can be divided into a square and a rectangle that is similar the the origional retangle
- rectange
- parallelgram with four fright angles
- paragraph prof
- written as sentences in a paragraph
- conjecture
- a conclusion you reach using inductive reasoning
- secant
- a line that intersects a circle at two points
- slant height
- the length of the altitude of a lateral face of the pyramid
- central angle
- an angle formed by two consecutive radii
- center
- the given point
- centroid
- the point of congruency of the medians, in a triangle
- preimage
- the original figure
- enlargement
- gets larger
- sector of a circle
- a region bounded by an arc of the circle and the two radii to the arc's endpoints
- trapezoid
- quadrilateral with exactly one pair of parallel sides
- similar
- occurs when corresponding angles are congruent, corresponding sides are proportional
- identity
- an equation that is true for all allowed values of the variable
- inscribed in
- when the sides of the polygon are tangent to the circle
- construction
- use a straight edge and a compass to draw a geometric figure
- biconditional
- when a conditional and its converse are true and you combine them
- scale drawing
- a drawing in which all lengths are proportional to corresponding actual lenghts
- theorem
- a conjecture that is proven
- collinear
- points that are on the same line
- prism
- a polyhedron with exactly two congurent, parallel faces
- cross section
- the intersection of a solid and a plane
- tangent
- length of leg opposite / length of leg adjacent
- radius
- the distance from the center to the vertex
- congruent circles
- circles whose radii are congurent
- rotation
- turn
- altitude of a triangle
- the perpendicular segment form a vertx to the line containing the opposite side
- isometry
- a transformation in which the preimage and image are congruent
- CPCTC
- corresponding parts of congruent triangles are congurent
- rotational symmetry
- its own image for some rotation of 180 degrees or less
- cross-product property
- cross multiplying
- concentric circles
- circles that lie in the same plane and have the same center
- regular polygon
- a polygon that is both equilateral and equiangular, its center is the center of the cercumscribec circle
- arc length (formula)
- m(arc)AB/360 X 2(pi)r
- concurrent
- when three or more lines intersect in one point
- dialation
- transformation
- altitude (prism)
- a perpendicular segment that joins the planes of the bases
- inscribed angle
- when the vertex of the angle is on the circe and the sides of the angle are chords of the circle
- convex polygon
- has no diagonal with points outside the polygon
- consecutive angles
- angles of a polygon that share a side (parallelogram-consecutive angles are supplementary)
- equilateral polygon
- a polygon whose sides are all congurent
- reflection
- flip across
- radius
- any segment with one endpoint on the circle and the other endpoint at the center of the circle
- corollary
- a statement that follows immediatley form a theorem
- distance from a point to a line
- the length of the perpendicular segment from the point to the line
- point
- (undefined) an ordered pair of values in a coordinate plane and named by a capital letter (a specific location)
- circumcenter of the triangle
- the point of cuncurrency of the perpendicular bisectors of a triangle
- base
- the third side
- orthocenter of the triangle
- three lines containing the altitudes of a triangle are congruent here
- lateral area
- the sum of the areas of the lateral faces
- right triangle
- the side opposite the right angles is the longest side
- great circle
- when the center of the circle is also the center of the sphere
- reflectional (line) symmetry
- the type of symmetry for which there is a reflection that maps a figure onto itself
- height (prism)
- the length of an altitude
- similarity ratio
- the ratio of corresponding linear demensions of two similar solids
- geometric probability
- a probability that uses a geometric model in which points represent outocmes
- conditional
- another name for an if-then statement
- median of a triangle (1)
- a segment whose endpoints are a vertex and the midpoint of the opposite side
- bases
- paralles faces
- pi
- the ratio of the circumference of a circle to its diameter
- midpoint
- a point that divides a segment into two congruent segments
- degrees
- a way to measure an angle
- line
- (undefined) a set of points in a plane that satisfy the same linear relationship (extend in opposite directions without end)
- translational symmetry
- a translation maps the tessellation onto itself
- regular pyramid
- a pyramid whose base is a regular polygon and whose lateral faces are congruent isosceles triangles
- locus
- a set of points, all of which meet a stated condition
- foundation drawing
- shows the base of a structure and the height of each part
- face
- each polygon
- right prisms
- one whose lateral faces are rectangular regoins and a lateral edge is an altitude
- lateral faces
- the other faces
- net
- a two-dimensional pattern that you can fold to form a three-dimensional figure
- orthographic drawing
- another way to show an three-dimensional figure
- inductive reasoning
- reasoning based on patterns you observe
- estended proportion
- 6/25 = 4/16 = 1/4
- altitude (2)
- a segment perpendicular to the line containing that base drawn from the side opposite the base
- parallel planes
- coplanar, do not intersect
- congurent polygons
- have congurent corresponding parts
- corresponding angles
- lie on the same side of the transversal, separated by two lines, same side on each line
- geometric mean
- the number (x) such that a/x = x/b, where a,b, and x are positive numbers
- perpendicular bisector
- a line, segment, or ray that is perpendicular to the segment at the midpoint, thereby bisecting the segment into two congurent parts
- parallel lines
- coplanar lines that do no intersect
- volume
- the space that a figure occupies
- vertex angle
- the two congruent sides
- base angle
- two angles that share a base of a trapezoid
- converse
- switches the hypothesis and the conclusion
- symmetry
- an isometry that maps the figure onto itself
- point symmetry
- 180 degrees rotational symmetry
- point of concurrency
- the point at which the lines intersect
- concave polygon
- has at least one diagonal with points outside the polygon
- tranformation
- a change in its position, shape, or size
- isometric drawing
- shows a corner view of a figure
- contrapositive
- switches the hyopthesis and the conclusion and negates both
- proportion
- a statement that two ratios are equal
- polygon
- closed plane figure with atleast three sides that are segments
- base of a parallelogram
- any of its sides
- hypothesis
- the part following "if"
- congruent segments
- two segments with the same length
- conclusion
- the part following "then"
- circumscribed about
- when the vertices of the polygon are on the circle
- circle
- the set of all points in a plane that are a given distance
- kite
- quadrilateral with two pairs of adjacent sides congruent and no opposite sides congruent
- space
- the set of all points
- translation
- a transformation that moves points the same distance and in the same direction
- inscribed in
- sides of the polygon are tangent to the circle
- same-side interior angles
- lie on the same side of the transversal, separated by two lines
- point of tangency
- the point where a circle and a tangent intersect
- tessellation (tiling)
- a repeating pattern of figures that completely covers a plane, without gaps or overlaps
- remote interior angles
- the two nonadjacent interior angles corresponding to each exterior ange of a triangle
- supplementary angles
- two angles whose measures have sum of 180
- scalar multiplication
- the multiplication of each entry in a matrix by the same number
- major arc
- an arc that is larger than a semicircle
- hypotenuse
- the longest side in a right triangle
- isosceles trapezoid
- nonparalledl opposite sides are congruent
- segment
- the part of a line consisting of two endpoint and all points between them
- apothem
- the distance from the center to the side
- square
- parallelogram with four congruent sides and four right angles
- counterexample
- an example for which the conjecture is incorrect
- initial point
- where the vector starts
- slope-intercept form
- y= mx+b
- alternate interior angles
- nonadjacent interior angles that lie on opposite sides of the transversal
- similar solids
- have the same shape, and all their corresponding dimensions are proportional
- adjacent arcs
- arcs of the same circle that have exactly one point in common
- opposite rays
- two collinear rays with the same endpiont (form a line)
- perpendicular lines
- two lines that intersect to form right angles
- adjacent angles
- two coplanar angles with a common side, a common vertex, and no common interior point
- cosine
- leg adjacent / hypotenuse
- angle bisector
- a ray that divides an angle into two congruent parts
- semicirlce
- half a circle
- composite space figure
- a three-dimensional figure that is the combination of two or more simpler figures
- angle of elevation
- the angle formed by a horizontal line and the line of sight to an object above the horizontal line
- equiangular polygon
- a polygon whose angles are all congruent
- ray
- the part of a line consisting of one endpoint and all the points of the line on one side of the endpiont
- height
- the length of the altitude
- midsegment
- a segment connecting the midpoints of two sides
- sphere
- the set of all points in space equidestant from a given pint called the center
- polyhedron
- a three-dimensional figure whose surfaces are polygons
- golden ratio
- 1.618 : 1
- base angles
- other angles (isosceles triangle)
- indirect measurement
- a way of measuring things that are difficult to measure directly
- pyramid
- a polyhedron in which one face can be any polygon and the other faces are triangles that meet at a common vertex
- tangent to a circle
- a line in the plane of the circle that intersects the circle in exactly one point
- circumference
- 2 (pi) r
- vertical angles
- two angles whose sides form two pairs of opposite rays
- coplanar
- points on the same plane
- similarity ratio
- the ratio of the lengths of corresponding sides
- resultant
- sum of two vectors
- postulate
- an accepted statement of fact
- truth value
- weither the statement is true of false
- rhombus
- a parallelogram with four congruent sides